ak.contents.ListOffsetArray
---------------------------

.. py:module: ak.contents.ListOffsetArray

Defined in `awkward.contents.listoffsetarray <https://github.com/scikit-hep/awkward/blob/e9dd2694cf5c6ccb1717358fe926816d8ecbfb9c/src/awkward/contents/listoffsetarray.py>`__ on `line 53 <https://github.com/scikit-hep/awkward/blob/e9dd2694cf5c6ccb1717358fe926816d8ecbfb9c/src/awkward/contents/listoffsetarray.py#L53>`__.

.. py:class:: ak.contents.ListOffsetArray(self, offsets, content, *, parameters=None)

ListOffsetArray describes unequal-length lists (often called a
"jagged" or "ragged" array). Like :py:obj:`ak.contents.RegularArray`, the
underlying data for all lists are in a contiguous ``content``. It is
subdivided into lists according to an ``offsets`` buffer, which specifies
the starting and stopping index of each list.

The ``offsets`` must have at least length 1 (corresponding to an empty array),
but it need not start with ``0`` or include all of the ``content``. Just as
:py:obj:`ak.contents.RegularArray` can have unreachable ``content`` if it is not
an integer multiple of ``size``, a ListOffsetArray can have unreachable
content before the start of the first list and after the end of the last list.

Like :py:obj:`ak.contents.RegularArray` and :py:obj:`ak.contents.ListArray`, a ListOffsetArray can
represent strings if its ``__array__`` parameter is ``"string"`` (UTF-8 assumed) or
``"bytestring"`` (no encoding assumed) and it contains an :py:obj:`ak.contents.NumpyArray`
of ``dtype=np.uint8`` whose ``__array__`` parameter is ``"char"`` (UTF-8 assumed) or
``"byte"`` (no encoding assumed).

ListOffsetArray corresponds to Apache Arrow
`List type <https://arrow.apache.org/docs/format/Columnar.html#variable-size-list-layout>`__.

To illustrate how the constructor arguments are interpreted, the following is a
simplified implementation of ``__init__``, ``__len__``, and ``__getitem__``:

.. code-block:: python


    class ListOffsetArray(Content):
        def __init__(self, offsets, content):
            assert isinstance(offsets, (Index32, IndexU32, Index64))
            assert isinstance(content, Content)
            assert len(offsets) != 0
            for i in range(len(offsets) - 1):
                start = offsets[i]
                stop = offsets[i + 1]
                if start != stop:
                    assert start < stop  # i.e. start <= stop
                    assert start >= 0
                    assert stop <= len(content)
            self.offsets = offsets
            self.content = content

        def __len__(self):
            return len(self.offsets) - 1

        def __getitem__(self, where):
            if isinstance(where, int):
                if where < 0:
                    where += len(self)
                assert 0 <= where < len(self)
                return self.content[self.offsets[where] : self.offsets[where + 1]]

            elif isinstance(where, slice) and where.step is None:
                offsets = self.offsets[where.start : where.stop + 1]
                if len(offsets) == 0:
                    offsets = [0]
                return ListOffsetArray(offsets, self.content)

            elif isinstance(where, str):
                return ListOffsetArray(self.offsets, self.content[where])

            else:
                raise AssertionError(where)



.. _ak-contents-listoffsetarray-offsets:

.. py:attribute:: ak.contents.ListOffsetArray.offsets



.. _ak-contents-listoffsetarray-copy:

.. py:method:: ak.contents.ListOffsetArray.copy(self, offsets=UNSET, content=UNSET, *, parameters=UNSET)



.. _ak-contents-listoffsetarray-__copy__:

.. py:method:: ak.contents.ListOffsetArray.__copy__(self)



.. _ak-contents-listoffsetarray-__deepcopy__:

.. py:method:: ak.contents.ListOffsetArray.__deepcopy__(self, memo)



.. _ak-contents-listoffsetarray-simplified:

.. py:method:: ak.contents.ListOffsetArray.simplified(cls, offsets, content, *, parameters=None)



.. _ak-contents-listoffsetarray-starts:

.. py:attribute:: ak.contents.ListOffsetArray.starts



.. _ak-contents-listoffsetarray-stops:

.. py:attribute:: ak.contents.ListOffsetArray.stops



.. _ak-contents-listoffsetarray-_form_with_key:

.. py:method:: ak.contents.ListOffsetArray._form_with_key(self, getkey)



.. _ak-contents-listoffsetarray-_to_buffers:

.. py:method:: ak.contents.ListOffsetArray._to_buffers(self, form, getkey, container, backend, byteorder)



.. _ak-contents-listoffsetarray-_to_typetracer:

.. py:method:: ak.contents.ListOffsetArray._to_typetracer(self, forget_length)



.. _ak-contents-listoffsetarray-_touch_data:

.. py:method:: ak.contents.ListOffsetArray._touch_data(self, recursive)



.. _ak-contents-listoffsetarray-_touch_shape:

.. py:method:: ak.contents.ListOffsetArray._touch_shape(self, recursive)



.. _ak-contents-listoffsetarray-length:

.. py:attribute:: ak.contents.ListOffsetArray.length



.. _ak-contents-listoffsetarray-__repr__:

.. py:method:: ak.contents.ListOffsetArray.__repr__(self)



.. _ak-contents-listoffsetarray-_repr:

.. py:method:: ak.contents.ListOffsetArray._repr(self, indent, pre, post)



.. _ak-contents-listoffsetarray-to_listoffsetarray64:

.. py:method:: ak.contents.ListOffsetArray.to_ListOffsetArray64(self, start_at_zero=False)



.. _ak-contents-listoffsetarray-to_regulararray:

.. py:method:: ak.contents.ListOffsetArray.to_RegularArray(self)



.. _ak-contents-listoffsetarray-_getitem_nothing:

.. py:method:: ak.contents.ListOffsetArray._getitem_nothing(self)



.. _ak-contents-listoffsetarray-_is_getitem_at_placeholder:

.. py:method:: ak.contents.ListOffsetArray._is_getitem_at_placeholder(self)



.. _ak-contents-listoffsetarray-_getitem_at:

.. py:method:: ak.contents.ListOffsetArray._getitem_at(self, where)



.. _ak-contents-listoffsetarray-_getitem_range:

.. py:method:: ak.contents.ListOffsetArray._getitem_range(self, start, stop)



.. _ak-contents-listoffsetarray-_getitem_field:

.. py:method:: ak.contents.ListOffsetArray._getitem_field(self, where, only_fields=())



.. _ak-contents-listoffsetarray-_getitem_fields:

.. py:method:: ak.contents.ListOffsetArray._getitem_fields(self, where, only_fields=())



.. _ak-contents-listoffsetarray-_carry:

.. py:method:: ak.contents.ListOffsetArray._carry(self, carry, allow_lazy)



.. _ak-contents-listoffsetarray-_compact_offsets64:

.. py:method:: ak.contents.ListOffsetArray._compact_offsets64(self, start_at_zero)



.. _ak-contents-listoffsetarray-_broadcast_tooffsets64:

.. py:method:: ak.contents.ListOffsetArray._broadcast_tooffsets64(self, offsets)



.. _ak-contents-listoffsetarray-_getitem_next_jagged:

.. py:method:: ak.contents.ListOffsetArray._getitem_next_jagged(self, slicestarts, slicestops, slicecontent, tail)



.. _ak-contents-listoffsetarray-_getitem_next:

.. py:method:: ak.contents.ListOffsetArray._getitem_next(self, head, tail, advanced)



.. _ak-contents-listoffsetarray-_offsets_and_flattened:

.. py:method:: ak.contents.ListOffsetArray._offsets_and_flattened(self, axis, depth)



.. _ak-contents-listoffsetarray-_mergeable_next:

.. py:method:: ak.contents.ListOffsetArray._mergeable_next(self, other, mergebool)



.. _ak-contents-listoffsetarray-_mergemany:

.. py:method:: ak.contents.ListOffsetArray._mergemany(self, others)



.. _ak-contents-listoffsetarray-_fill_none:

.. py:method:: ak.contents.ListOffsetArray._fill_none(self, value)



.. _ak-contents-listoffsetarray-_local_index:

.. py:method:: ak.contents.ListOffsetArray._local_index(self, axis, depth)



.. _ak-contents-listoffsetarray-_numbers_to_type:

.. py:method:: ak.contents.ListOffsetArray._numbers_to_type(self, name, including_unknown)



.. _ak-contents-listoffsetarray-_is_unique:

.. py:method:: ak.contents.ListOffsetArray._is_unique(self, negaxis, starts, parents, outlength)



.. _ak-contents-listoffsetarray-_unique:

.. py:method:: ak.contents.ListOffsetArray._unique(self, negaxis, starts, parents, outlength)



.. _ak-contents-listoffsetarray-_argsort_next:

.. py:method:: ak.contents.ListOffsetArray._argsort_next(self, negaxis, starts, shifts, parents, outlength, ascending, stable)



.. _ak-contents-listoffsetarray-_sort_next:

.. py:method:: ak.contents.ListOffsetArray._sort_next(self, negaxis, starts, parents, outlength, ascending, stable)



.. _ak-contents-listoffsetarray-_combinations:

.. py:method:: ak.contents.ListOffsetArray._combinations(self, n, replacement, recordlookup, parameters, axis, depth)



.. _ak-contents-listoffsetarray-_reduce_next:

.. py:method:: ak.contents.ListOffsetArray._reduce_next(self, reducer, negaxis, starts, shifts, parents, outlength, mask, keepdims, behavior)



.. _ak-contents-listoffsetarray-_rearrange_prepare_next:

.. py:method:: ak.contents.ListOffsetArray._rearrange_prepare_next(self, outlength, parents)



.. _ak-contents-listoffsetarray-_validity_error:

.. py:method:: ak.contents.ListOffsetArray._validity_error(self, path)



.. _ak-contents-listoffsetarray-_nbytes_part:

.. py:method:: ak.contents.ListOffsetArray._nbytes_part(self)



.. _ak-contents-listoffsetarray-_pad_none:

.. py:method:: ak.contents.ListOffsetArray._pad_none(self, target, axis, depth, clip)



.. _ak-contents-listoffsetarray-_to_arrow:

.. py:method:: ak.contents.ListOffsetArray._to_arrow(self, pyarrow, mask_node, validbytes, length, options)



.. _ak-contents-listoffsetarray-_to_backend_array:

.. py:method:: ak.contents.ListOffsetArray._to_backend_array(self, allow_missing, backend)



.. _ak-contents-listoffsetarray-_remove_structure:

.. py:method:: ak.contents.ListOffsetArray._remove_structure(self, backend, options)



.. _ak-contents-listoffsetarray-_drop_none:

.. py:method:: ak.contents.ListOffsetArray._drop_none(self)



.. _ak-contents-listoffsetarray-_rebuild_without_nones:

.. py:method:: ak.contents.ListOffsetArray._rebuild_without_nones(self, none_indexes, new_content)



.. _ak-contents-listoffsetarray-_recursively_apply:

.. py:method:: ak.contents.ListOffsetArray._recursively_apply(self, action, depth, depth_context, lateral_context, options)



.. _ak-contents-listoffsetarray-to_packed:

.. py:method:: ak.contents.ListOffsetArray.to_packed(self, recursive=True)



.. _ak-contents-listoffsetarray-_to_list:

.. py:method:: ak.contents.ListOffsetArray._to_list(self, behavior, json_conversions)



.. _ak-contents-listoffsetarray-_to_backend:

.. py:method:: ak.contents.ListOffsetArray._to_backend(self, backend)



.. _ak-contents-listoffsetarray-_awkward_strings_to_nonfinite:

.. py:method:: ak.contents.ListOffsetArray._awkward_strings_to_nonfinite(self, nonfinit_dict)



.. _ak-contents-listoffsetarray-_is_equal_to:

.. py:method:: ak.contents.ListOffsetArray._is_equal_to(self, other, index_dtype, numpyarray, all_parameters)